This invention relates in general to a private telephone system and, more particularly, to a network-based private telephone system in which communication between the telephones is effected by transmitting message units that contain digital information through the network.
In a situation where several telephones are required, the traditional approach has been to install special wiring that serves as dedicated telephone wiring. In recent years, however, the use of computers has expanded, and the need for communication between computers has caused organizations to add an additional level of wiring, which is a network to interconnect the computers.
It has previously been recognized that it can be advantageous and cost-effective to use a single network of wiring to effect both telephone services and communication between computers. To this end, telephones have been developed which can be coupled to a traditional computer-type network, such as a network conforming to the industry standard commonly known as Ethernet. While these existing network-based telephone systems have been generally adequate for their intended purposes, they have not been satisfactory in all respects.
More specifically, these existing network-based telephone systems normally include several telephones which are coupled to the network, and an additional stand-alone computer which is also coupled to the network and which serves as a central controller. The central controller acts as a master, and treats the telephones as slaves. The system cannot operate without this central controller, which is commonly referred to as a call manager server or a Key System Unit (KSU). The central controller is particularly critical where the system is coupled to one or more telephone lines of a conventional telephone network, in order to permit any of the telephones in the system to place or receive calls using those telephone lines.
In comparison to the cost of the telephones, the central controller is a relatively expensive device. In fact, in a small system which involves only a few telephones, the cost of the central controller may be several times the combined cost of the telephones. As a result, such a small system may be far too expensive to be reasonably used in a home or a small business. A further consideration is that the administration of these existing systems requires special hardware and/or software tools, for example to move a given telephone or to change the number assigned to a given telephone. Use of these tools may necessitate a level of operator training or sophistication which makes these systems highly unattractive for use in a home or small business.
From the foregoing, it may be appreciated that a need has arisen for a method and apparatus for providing network-based telephone capability without the need for a central controller, and with simple and easy-to-learn provisions for routine system administration. According to the present invention, a method and apparatus are provided to address this need, and involve: providing a network through which can be transmitted message units that contain information in a digital format; coupling to the network a plurality of separate telephone units which are each usable by a person, and which have therein a control portion that is integral in its entirety to the telephone units and transmits message units through the network in order to effect communication between the telephone units; and causing the control portion to respond to a manual event at a first of the telephone units by selectively establishing audio communication between the first telephone unit and a second of the telephone units based on transmission of message units between the first and second telephone units.